1. Unit 4 Soil Science

2. Importance of Soil What is soil? Holds water and nutrients for plants Natural filter Stores and recycles nutrients Fertile soil = higher yields Erosion

3. Soil Formation 5 Factors – Parent material – Climate – Biological factors – Topography – Time

4. Soil Profile O = organic matter or humus A = organic and inorganic E = little organic matter due to eluviation B = leached or washed materials C = parent material

5. Organic and Inorganic Soils Organic Soils Composed mostly of decayed plant and animal matter Inorganic Soils Composed mostly of minerals

6. Soil Types and Texture

7. Soil pH Affects how nutrients and chemical are absorbed by plants Some plants like more acidic soil Others prefer a more basic soil How is soil pH changed?

8. Water and Nutrients in the Soil Sand Silt Clay Large pore spaces allow water and nutrients to move quickly Small pore spaces tightly hold onto water and nutrients

9. Soil Erosion Topsoil Nutrients are lost Water erosion Wind erosion Management – Crop rotation – Cover crops – Rotational grazing – Tillage practices

10. Soil Ecosystems Plants Burrowing Mammals Arthropods Earthworms Microorganisms